A method of controlling a wavelength of a wavelength tunable laser module includes: referring to data of measured frequencies and wavelength filter control values at two or more points for each basic frequency channel, the data being stored in a memory of a controller; selecting the basic frequency channel closest to a frequency of laser light that a laser light source is instructed to emit; calculating a first wavelength filter control value for providing the instructed frequency of laser light from the data of the measured frequencies allocated to the basic frequency channel closest to the instructed frequency and the wavelength filter control values; and controlling the transmission characteristic of a wavelength filter using the first wavelength filter control value.

Systems and methods for providing transmission and reception of hybrid time and wavelength division multiplexed signals on passive optical networks are provided. Networks that use shared transmission media avoid interference between transmitters by restricting the times or wavelengths that given transmitters may use to transmit their messages. The hybrid broadcast WDM TDM PON architecture enables transmitters to use multiple fixed wavelengths for parallel optical transmission within given timeslots to avoid interference with other transmitters and make use of inexpensive fixed optical components to gain a speed advantage over existing architectures while making use of their deployed infrastructure. A single scheduling manager controls the timeslots of upstream and downstream transmissions, which make use of existing standards.

Provided is an optical transceiver including: a receiver configured to receive an optical transmission signal including wavelength information from another optical transceiver through a multiplexer/demultiplexer connected to the receiver; and a controller configured to identify a reception wavelength for communication with the other optical transceiver and to determine a wavelength corresponding to the reception wavelength as a transmission wavelength for communication with the other optical transceiver, based on the wavelength information included in the optical transmission signal.

A system and method for performing an in-service optical time domain reflectometry test, an in-service insertion loss test, and an in-service optical frequency domain reflectometry test using a same wavelength as the network communications for point-to-point or point-to-multipoint optical fiber networks while maintaining continuity of network communications are disclosed.

A method in a first level aggregation node of a transport network is disclosed. The transport network comprises the first level aggregation node, a second level aggregation node and a Passive Optical Network. T the method comprises receiving, from the second level aggregation node, a plurality of wavelength division multiplexing (WDM) channels having wavelengths in a first spectrum section and generating at least one passive optical channel having a wavelength in a second spectrum section, different to the first spectrum section. The method further comprises combining at least some of the WDM channels received from the second level aggregation node with the at least one passive optical channel, and forwarding the combined WDM channels and passive optical channel to a termination node in the Passive Optical Network. Also disclosed are a method in a termination node of a transport network, a first level aggregation node, a termination node and a computer program.

Provided is an optical transceiver including: a receiver configured to receive an optical transmission signal including wavelength information from another optical transceiver through a multiplexer/demultiplexer connected to the receiver; and a controller configured to identify a reception wavelength for communication with the other optical transceiver and to determine a wavelength corresponding to the reception wavelength as a transmission wavelength for communication with the other optical transceiver, based on the wavelength information included in the optical transmission signal.

A system and method for performing an in-service optical time domain reflectometry test, an in-service insertion loss test, and an in-service optical frequency domain reflectometry test using a same wavelength as the network communications for point-to-point or point-to-multipoint optical fiber networks while maintaining continuity of network communications are disclosed.

An IC-TROSA point-to-multipoint optical network system includes a point-to-multipoint optical network coupled to a hub device configured to transmit first and second optical signals via respective first and second transmit ports. A subscriber coherent optical transceiver device on a subscriber device is coupled to the point-to-multipoint optical network, and includes a subscriber signal processing subsystem that receives optical signals from the hub device, and determines whether the subscriber coherent optical transceiver device is configured to receive the optical signals via the first or second transmit port on the hub device. If configured to receive the optical signals via the first transmit port, the subscriber signal processing subsystem performs first signal processing operations to decode the optical signals. If configured to receive the optical signals via the second transmit port, the subscriber signal processing subsystem performs second signal processing operations to decode the optical signals.

Consistent with the present disclosure, an encoder circuit is provided at a transmit side of an optical fiber link that maps an input sequence of bits of fixed length k a sequence of symbols of a codeword of length n, such that the symbols of the codeword define a predetermined transmission probability distribution. Preferably, each symbol of the codeword is generated during a corresponding clock cycle, such that after n clock cycles, a complete codeword corresponding to the input bit sequence is output. On a receive end of the link, a decoder is provided that outputs the k-bit sequence every n clock cycles. Accordingly, buffers need not be provided at the output of the encoder and the input of the decoder, such that processing of the input sequence, codewords, and output sequence may be achieved efficiently without large buffers and complicated circuitry. Moreover, the input sequence, with any binary alphabet may be matched to a desired output distribution with any arbitrary alphabet. Accordingly, probabilistic constellation shaping may be achieved over constellations of arbitrary size. In addition, relatively long codewords, may be encoded and decoded with the apparatus and method disclosed herein. Accordingly, for a fixed SNR a higher SE (more bits per symbol) can be achieved. Alternatively, for a fixed SE, a lower SNR may be sufficient. Moreover, the resulting SE may be finely tailored to a particular optical link SNR to provide data transmission rates that are higher than the low order modulation formats that would otherwise be employed for optical signals carried by such links.

An optical network communication system includes an optical hub, an optical distribution center, at least one fiber segment, and at least two end users. The optical hub includes an intelligent configuration unit configured to monitor and multiplex at least two different optical signals into a single multiplexed heterogeneous signal. The optical distribution center is configured to individually separate the at least two different optical signals from the multiplexed heterogeneous signal. The at least one fiber segment connects the optical hub and the optical distribution center, and is configured to receive the multiplexed heterogeneous signal from the optical hub and distribute the multiplexed heterogeneous signal to the optical distribution center. The at least two end users each include a downstream receiver configured to receive one of the respective separated optical signals from the optical distribution center.